I am new to Revit and this forum. I am using Revit Structure 2014 as I work for a structural engineering consultancy.

I have a project where there is an existing steel framed building that is to be refurbished. This includes raising a floor level, creating service shafts, infilling floor voids and adding another storey on top.

I was wondering the best way to differentiate between the existing steelwork structure and the new steelwork? I might still be thinking as if i'm using CAD where I would create separate layers with different colours so I can easily see the difference and turn off and on when required. Is there a way to create an 'Existing Structural Column' layer for example?

The same applies to walls, floors, roofs etc... where I have existing and new.

I have a new build project that I would like to split into sections (ie: office area, workshop area and above roof plant support). The main reason for splitting it up is that it is quite a complicated shape with curves in all directions possible and the interface between the office and workshop is a 'mess' of beams and columns in an irregular pattern to fit within the architects wall layout. I don't want to go any smaller than 1:100 when I create the drawing sheets as it becomes too difficult to read. At 1:100 the entire building will not fit on an A1 sheet though! If I could separate it then the office area and the workshop area could fit on @ 1:75. Would phasing be the best way to do this or is there another way?

I have a new build project that I would like to split into sections (ie: office area, workshop area and above roof plant support). The main reason for splitting it up is that it is quite a complicated shape with curves in all directions possible and the interface between the office and workshop is a 'mess' of beams and columns in an irregular pattern to fit within the architects wall layout. I don't want to go any smaller than 1:100 when I create the drawing sheets as it becomes too difficult to read. At 1:100 the entire building will not fit on an A1 sheet though! If I could separate it then the office area and the workshop area could fit on @ 1:75. Would phasing be the best way to do this or is there another way?

No, Phasing is purely used for showing how a project changes over time. You new question concerns how to best display the views on a sheet, when they are two large for a single sheet. I would recommend using "Dependent Views" and Split Lines-and actually put the two "part-plans" on two seperate sheets.